Helianthus species

Click on the images below to see larger versions.

Scientific Name Helianthus annuus USDA PLANTS Symbol HEAN3
Common Name Sunflower, Common Sunflower ITIS Taxonomic Serial No. 36616
Family Asteraceae (Sunflower) SEINet
Reference
Click Here
Description Habitat: Plains to montane (3300 to 9000 ft.); dry soils, disturbed areas, fence rows. Widely distributed.
Plant: Erect annual, widely branching 1 to 8 feet tall, rough, hairy stems.
Leaves: Rough, alternate, ovate to ovate-oblong with cordate bases; blades 4 to 16 inches long and nearly as wide on long petioles.
Inflorescence: Bright yellow composite flower heads 3 to 5 inches across with 17 to 30 rays surrounding normally dark brown central disk florets; wide phyllaries ovate to lance-ovate, with ciliate margins, and abruptly narrowed, pointed tips.
Bloom Period: June to October.
References: "Flora of Colorado" by Jennifer Ackerfield, "Wildflowers of the Rocky Mountains" by Carl Schreier and SEINet.
BONAP Distribution Map

Colorado Status:
Native
Scientific Name Helianthus petiolaris ssp. fallax USDA PLANTS Symbol HEPEF
Common Name Prairie Sunflower ITIS Taxonomic Serial No. 36673
Family Asteraceae (Sunflower) SEINet
Reference
Click Here
Description Life zones and habitat: Plains to foothills (3900 to 8200 ft.); sunny, dry areas and semi-desert.
Plant: Erect annual 1-1/2 to over 6 feet tall, often-branched stem with fine hairs.
Leaves: Mostly stem leaves, lanceolate to ovate, 1-1/2 to 6 inches long, petiolate; lower leaves are narrow, more than twice as wide as long; may be dotted with glands, hairy underneath, small teeth along edges.
Inflorescence: Single composite flowers 2 to 3 inches across with 10 to 20 yellow rays and 50 to 100+ reddish disk florets in the center; involucre phyllaries are oblong-lanceolate or oblong-lanceolate and relatively wide compared to ssp. fallax (above); peduncle usually has no leafy bract subtending the head.
Bloom Period: June to October.
References: "Flora of Colorado" by Jennifer Ackerfield, Flora of North America and SEINet.
BONAP Distribution Map

Colorado Status:
Native
Scientific Name Helianthus petiolaris ssp. petiolaris USDA PLANTS Symbol HEPEP
Common Name Prairie Sunflower ITIS Taxonomic Serial No. 36672
Family Asteraceae (Sunflower) SEINet
Reference
Click Here
Description Life zones and habitat: Plains to foothills (3300 to 6500 ft.); dry sandy soils in open areas.
Plant: Erect annual 1-1/2 to over 6 feet tall, often-branched stem with fine hairs.
Leaves: Mostly stem leaves, lanceolate to ovate, 1-1/2 to 6 inches long, petiolate; lower leaves are about twice as wide as long; may be dotted with glands, hairy underneath, small teeth along edges.
Inflorescence: Single composite flowers 2 to 3 inches across with 15 to 30 yellow rays and 50 to 100+ reddish disk florets in the center; involucre phyllaries are oblong-lanceolate to lanceolate and relatively narrow compared to ssp. petiolaris (below); peduncle with leafy bract subtending the head.
Bloom Period: June to October.
References: "Flora of Colorado" by Jennifer Ackerfield, Flora of North America and SEINet.
BONAP Distribution Map

Colorado Status:
Native

© Tom Lebsack 2021